SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7ebea3198ad0d0d6ddcf9b12c553142ca095a996afd599eddd57bf291724980' 
  AND token = '0qdx8biOtPICFXL9E4zc2zq0JXvOm93vHGJahNhDvBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}